Device for applying and/or spreading liquid or pasty substances for coating surfaces

ABSTRACT

The invention relates to a device for applying and/or spreading liquid or pasty substances for coating surfaces, especially paists, varnishes and lacquers on the surface of objects ( 2 ). The device has at least two pinions ( 7, 7 ′) the axes of which are arranged substantially parallel in relation to the object&#39;s surface to be coated. The spindles are provided with circumferential brush-like spreaders ( 8 ). At least one spindle can be moved across the surface of the object, with the object being moved along the brush-like spreaders.

FIELD OF THE INVENTION

The present invention relates to an apparatus for applying and/orspreading liquid or pasty substances for coating surfaces, in particularpaints, varnishes and lacquers, on the surfaces of workpieces.

BACKGROUND OF THE INVENTION

It is known to coat the surfaces of workpieces with liquid or pastysubstances, for example paints, varnishes or lacquers, so as to protectthem and/or to improve their appearance. To this end, the saidsubstances are generally sprayed, rolled or poured onto the surfaces ofthe workpieces.

When rolling or pouring paints, varnishes or lacquers onto the surfacesof workpieces it is virtually impossible to obtain thin and very uniformcoatings, in particular when the surfaces of the workpieces are uneven.

In the case of such surfaces, for example profiled surfaces, applicationof the coating substance by means of a spraying technique thereforeremains the sole option for obtaining a somewhat more uniform coating.However, it is known even in the spraying technique that largerquantities of coating substance collect in small depressions on thesurface than in the surrounding regions. This results in a locallythicker layer thickness when the coating has been applied. Particularlywhen the coating substance is a paint, this may result in a nonuniformintensity of color.

A further, generally known problem with the use of the sprayingtechnique is the high consumption of coating substance and theenvironmental impact associated therewith, since during normalapplication by spraying, the process causes a not inconsiderable part ofthe coating substance to fall next to the workpiece to be coated.

It is therefore the object of the invention to apply and/or uniformlyspread liquid or pasty substances for coating surfaces, in particularpaints, varnishes and lacquers, on the surfaces of workpieces, inparticular also on slightly profiled surfaces.

SUMMARY OF THE INVENTION

According to the invention, the object is achieved by an apparatus forapplying and/or spreading liquid or pasty substances.

The apparatus according to the invention is ideally suitable forspreading liquid or pasty substances for coating surfaces, inparticular, paints, varnishes or lacquers, which have been applied ontothe surface(s) of the workpieces in the apparatus or in a precedingmanufacturing step. Brush-like spreaders which are fitted to thecircumference of spindles are used for the application and/or spreading.In the process, at least one of the spindles having the brush-likespreaders moves approximately parallel over the workpiece surface to becoated, while the workpiece is at the same time moved past the apparatusby a conveying device.

Surface profiles and slight unevennesses of the surface are absorbed bythe elasticity in the brush-like spreaders to the extent that even hereapplication and/or uniform spreading of the liquid or pasty substancetakes place.

The practical use of the apparatus according to the invention resides ininstalling it as a coating station between a station for the substanceapplication by means of a known technique, for example by means of aroller machine or by pouring, and a generally known and conventionaldrying station, for example a UV drying instalation, or in placing it asa coating station having integrated substance application directly infront of the drying station.

The arrangement of the brush-like spreaders fulfils the purpose ofbringing the applied excess of coating substance into regions, such asdepressions or profiled areas, and of spreading it there. A very uniformcoating over the entire surface can thereby be achieved.

In a particularly advantageous manner, in one embodiment of theinvention the spindles rotate about their own axis and at least two ofthe spindles are guided over the workpieces to be coated in a rotationalmovement running approximately parallel to the surface of the workpieceby a common rotor. A further rotating spindle, but which is fitted withits axis fixed in position, can be fitted at that end of the coatingstation which faces the drying station. This positionally fixed spindlewith its own driving unit has the task of leveling the processing traceswhich may still be detectable and which the moveable spindles might haveleft behind on the surface to be coated.

In a further, very favorable embodiment, the brush-like spreaders arefitted on the circumference of the spindles at an acute angle to theaxis of the said spindles. Because of the rotations of the spindles andthe translatory movement of the workpieces past the apparatus, thefriction of the bristles against the surface which is to be coatedresults in an equalizing movement of the bristles. This means that thearrangement of the bristles at an acute angle to the axis of thespindles can result in an oscillating movement of the bristles on thesurface of the workpiece which is to be coated, which movementcontributes to a very uniform spreading of the liquid or pasty coatingsubstance. The coating substance is virtually “rubbed” into the surface.

In addition, because of the oscillating movement of the brush-likespreaders and the virtually ideal spreading of the applied coatingsubstance which is made possible as a result, a considerable quantity ofthis coating substance can be saved.

In a further, very advantageous embodiment of the invention, thebrush-like spreaders are fitted on disk-like holders which can beplugged onto the spindles. They can be pushed onto the spindle inalternating fashion with one or more spacer disks in a manner secureagainst rotation. The individual elements can then finally also beclamped with respect to one another on the spindle by means of afastening device. In this case, the use of angle-equalizing disks alsomakes it possible for different angular positions of the bristles withrespect to the axis of the spindle to be realized in a simple manner.

This very flexible design of the coating station can thus be adaptedrapidly and simply to virtually any desired task and any coatingsubstance. Thus, for example by a change in the distance between thebrush-like spreaders, the installation can be adapted without greatoutlay to the present situation, for example to the viscosity of thecoating substance used or to the condition of the surface of theworkpieces to be coated. The advantages obtained thereby in the savingon set-up time, manufacturing sequence and ultimately in the logisticsare obvious.

However, the arrangement of the brush-like spreaders on the disk-likeholders provides yet further advantages, particularly also in thehandling of the parts. Thus, the disk-like holders together with theirbrush-like spreaders are considerably more easy to handle during storageand dispatch and are damaged less frequently than complete spindlesfitted with brush-like spreaders.

The advantageous properties of the apparatus according to the inventionare also further assisted in that the rotor, the moveable spindles andthe at least one positionally fixed spindle can be set completelyindependently of one another in their rotational speed and direction ofrotation.

If the coating station is used with an integrated substance application,as one of the advantageous refinements of the invention envisages, theliquid or pasty substance for coating surfaces can be picked up by therevolving brush-like spreaders on that side of the spindles which facesaway from the surfaces to be coated.

In order to avoid workpieces which are to be coated from tilting andrising up between the spindles having the brush-like spreaders, in aparticularly advantageous embodiment of the invention, holding-downclamps can be provided between the spindles. In a particularly favorabledesign, these holding-down clamps, which can partly also be movedtogether with the moveable spindles, have beveled or rounded regions ontheir edge regions facing the spindles.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantageous refinements of the invention emerge from the othersubclaims and from the exemplary embodiment described below withreference to the drawings, in which:

FIG. 1 shows a schematic illustration of a possible manufacturing linefor coating surfaces of workpieces;

FIG. 2 shows a sectional illustration through a spindle havingbrush-like spreaders;

FIG. 3 shows a disk-like holder with brush-like spreaders; and

FIG. 4 shows a schematic section through a holding-down clamp accordingto the line IV—IV in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1, a possible manufacturing line 1 for coating surfaces 2 a ofworkpieces 2 can be seen. The manufacturing line 1 has a delivery table3 from which the workpieces 2 to be coated are moved through themanufacturing line 1 on a conveying device 4, for example a conveyorbelt 4.

In the exemplary embodiment illustrated, this is followed by a rollermachine 5 which is designed in a known manner and in which the actualapplication of the coating substance, in particular paint in this case,onto the surface 2 a of the workpieces 2 takes place. Following thisroller machine 5 there is then, for the purpose of application in theregions not coated by the roller machine, for example profiled areas,and for the uniform spreading of the paint, a coating station 6 havingfour moveable spindles 7 and a spindle 7′ which is fitted with its axisfixed in position with respect to the apparatus. The spindles 7, 7′ bearbrush-like spreaders 8 on their circumference. In this arrangement, thefour moveable spindles 7 are arranged such that they can rotate about acommon rotor 9 and the positionally fixed spindle 7′ is arranged at theend of the coating station, in the direction of passage of theworkpieces 2, and has its own driving unit 10. In the operating state ofthe coating station 6 the moveable spindles 7 and the positionally fixedspindle 7′ rotate about their respective axis.

After the paint has been deposited onto the surface 2 a of theworkpieces 2 to be coated in the roller machine 5, the workpieces 2 passthrough the coating station 6. In the process, they move on the conveyorbelt 4 past the rotating spindles 7, 7′ with the moveable spindles 7additionally still moving about the common rotor 9. As this happens, thebrush-like spreaders 8 brush at least with the ends of their bristlesover the surface 2 a to be coated, apply more paint in the processand/or spread the paint which has been applied very uniformly. After theprocessing by the brush-like spreaders 8 of the moveable spindles 7processing traces may possibly still remain on the surfaces 2 a of theworkpieces 2. These processing traces are leveled by the rotatingspindle 7′, which is fitted in a positionally fixed manner at the end ofthe coating station 6.

Holding-down clamps 11 can be seen between the spindles 7, 7′, the saidclamps having the task of preventing the workpieces 2 from tilting andrising up in the coating station 6.

After having passed through the coating station 6, the workpieces 2 areconveyed by the conveyor belt 4 to a drying station 12 of a known typeof construction. The drying station 12 is indicated here schematicallyas a two-stage UV-drying installation 12. After having passed throughthe drying station 12, the workpieces 2 pass to a removal table 13 andcan be removed there for further processing, if that is desired, or fordispatch of the workpieces 2.

The very simple manufacturing line 1 selected for the schematicillustration in FIG. 1 is, of course, just one option for the use of thecoating station 6. Of course, other, larger manufacturing lines 1 arealso conceivable, in particular those having multi-stage coatingprocesses. Thus, for example after the UV-drying installation 12,grinding of the surfaces 2 a could take place and this could then befollowed by one or more further applications of paint by subsequentcoating stations 6 and a plurality of further drying stations 12 beforethe workpieces pass onto the removal hi table 13. Also, one or morecoating stations 6 having an integrated application of paint areconceivable; they could even further simplify the manufacturing line 1.

FIG. 2 shows a section through one of the moveable spindles 7 togetherwith a rotor 9, which is just illustrated schematically. A workpiece 2lying on the conveyor belt 4 which is indicated can be seen below themoveable spindle 7 with the bristles of the brush-like spreaders 8brushing over it.

The design described below applies by analogy to the design of thepositionally fixed spindle 7′.

A plurality of disk-like holders 14 are clamped onto the spindle 7together with an inner closure element 15, a plurality of spacer disks16 and an outer closure element 17. In this arrangement, both thespindle 7 and central openings 18 of the disk-like holders 14, thespacer disks 16 and the two closure elements 15, 17, by means of whichopenings all the latter can be clamped onto the spindle 7, are designedas a hexagon profile.

The hexagon profile means that the disk-like holders 14, the spacerdisks 16 and the two closure elements 15, 17 can no longer rotate withrespect to the spindle 7 after having been clamped on. In addition, allof the abovementioned elements also have projections 19 and depressions19′ which engage in the depressions 19′ and the projections 19 of thefollowing element in each case and thus permit an interlockingconnection of the disk-like holders 14, the spacer disks 16 and the twoclosure elements 15, 17 with respect to one another.

The outer closure element 17, which is clamped on on that side of thespindle 7 which faces away from the rotor 9, is of cup-like design.After being clamped onto the spindle 7 it can be clamped against thespindle 7 with a fastening element 20, via a screw 20 in this case. Thedisk-like holders 14, the spacer disks 16 and the inner closure element15 are therefore also clamped with respect to one another. Anon-positive fastening of the disk-like holders 14, the spacer disks 16and the two closure elements 15, 17 is therefore additionally alsoobtained.

The entire system is very flexible and the individual parts can easilybe displaced and/or interchanged in order to refit the coating station6.

In the exemplary embodiment illustrated, the disk-like holders 14 areconstructed in such a manner that they are clamped on at an acute angledeviating from 90° with respect to the axis of the spindle 7. In thiscase, the two closure elements 15, 17 additionally also serve asangle-equalizing disks 15, 17 which have, on their one side, the acuteangle which deviates from 90° and, on their other side, a right anglewith respect to the axis of the spindle 7.

As is indicated by the arrow 21 in FIG. 2, the moveable spindle 7rotates about its own axis. In this arrangement, the rotational speedand the direction of rotation of each moveable spindle 7 can be setindependently of the other moveable spindles 7. In addition, all fourmoveable spindles 7 rotate jointly about the rotor 9, as is indicated bythe arrow 22. A further movement component is a translation of theworkpieces 2 underneath the coating station 6 which is produced by theconveyor belt 4.

The spindle 7′ which is fitted in a positionally fixed manner inprinciple has the same design, with the fastening element 20 coming torest here on the side facing away from the driving unit 10 of thepositionally fixed spindle 7′. In addition, only two movements takeplace here, namely the rotation of the positionally fixed spindle 7′ andthe translation of the workpieces 2.

By means of the combination of the obliquely set, brush-like spreaders8, the rotation of the spindles 7, 7′ and because of the friction of thebristles of the brush-like spreaders 8 against the surface 2 a to becoated, an oscillating, equalizing movement (indicated by the arrow 23)of the bristles of the brush-like spreaders 8 occurs, as a result ofwhich the paint which has been applied is spread in an ideal manner overthe surface 2 a of the workpieces 2 passing below the coating station 5.

In FIG. 3, one of the disk-like holders 14 can be seen. The spacer disks16, which are available in a number of thicknesses, have virtually thesame design as the disk-like holders 14, but without having brush-likespreaders 8.

Projections 19 can be seen on the disk-like holder 14, which projectionsengage in an interlocking manner in the following, disk-like holder 14and the following spacer disk 16, when the said holder and spacer diskare clamped together onto the spindle 7, 7′ and clamped in place. Inthis arrangement, the central opening 18 is formed in the hexagonprofile which has already been described, and the brush-like spreaders 8are glued in place in cutouts (which cannot be seen in the illustration)which point radially to the central opening 18 on a surface 24 formingthe circumference of the disk-like holder 14.

Of course, different disk-like holders 14 having differing brush-likespreaders 8 are conceivable. In particular, the length and stiffness ofthe bristles of the brush-like spreaders 8 and their angular settinggive rise to a very large number of options which can be used easily, bysimple refitting of the coating station 6, for adapting the coatingstation 6 in a flexible manner to the surfaces 2 a to be coated in eachcase of the respective workpieces 2.

In FIG. 4, a section through the holding-down clamp 11 can be seen.Holding-down clamps 11 of this type are in each case arranged betweenthe spindle 7, 7′ with their brush-like spreaders 8 and move partiallytogether with the moveable spindles 7. They have the task of preventingthe workpieces 2 which are to be coated from tilting and rising upbetween the spindles 7, 7′. Such rising up of the workpieces 2, whichmay occur predominantly in the case of wooden workpieces 2 which havealready been damaged and distorted, could damage the coating station 6and would in any case force the entire manufacturing line 1 to come to astandstill.

The holding-down clamps 11 have rounded or beveled regions on their edgeregions 25 which face the spindles 7, 7′, with the result that theprocessing of the workpieces 2 to be coated by the brush-like spreaders8 is not adversely affected.

What is claimed is:
 1. An apparatus for one of applying and spreading acoating onto a surface (2 a) of a workpiece (2), the apparatuscomprising: at least two movable spindles and one fixed spindle (7, 7′),with each of the spindles (7, 7′) having a rotational axis arrangedapproximately parallel to the surface (2 a) of the workpiece (2) to becoated,.each of the spindles (7, 7′) having a plurality of brushspreaders (8) supported about a circumference thereof, and the at leasttwo movable spindles (7) being movable over the surface (2 a) of theworkpiece (2); and the two movable spindles (7) are supported by arotatable common rotor (9), the two movable spindles and the one fixedspindle (7, 7′) each rotate about a respective rotational axis, and thetwo movable spindles are guided such that the two movable spindles (7)rotate in a plane defined by the rotatable common rotor (9).
 2. Theapparatus according to claim 1, wherein the rotational axis of one ofthe two spindles (7′) is fixed, and a driving unit (10) suppliesrotational drive to the one fixed spindle (7′) so that the one fixedspindle (7′) only rotates.
 3. The apparatus according to claim 1,wherein the brush spreaders (8) are arranged around the circumference ofeach of the two spindles (7, 7′) so as to extend at an acute angle withrespect to the rotational axis of the respective spindle (7, 7′).
 4. Theapparatus according to claim 1, wherein a rotational speed and arotational direction of the common rotor (9) and a rotational speed androtational direction of the driving unit (10) are controllableindependently of one another.
 5. The apparatus according to claim 1,wherein the coating is deposited on surface (2 a) of the workpiece (2)by a machine (5) prior to the workpiece (2) entering the apparatus. 6.The apparatus according to claim 1, wherein the coating is deposited onsurface (2 a) of the workpiece (2) when the workpiece (2) is locatedwithin the apparatus.
 7. The apparatus according to claim 1, whereineach spindle (7, 7′) comprises a plurality of disk holders (14) with aplurality of cutouts formed about a circumference thereof, and thespreader brushes (8) are glued in the cutouts of the disk holders (14).8. The apparatus according to claim 7, wherein each disk holder (14) hasa central opening (18) therein, and the central opening (18) of eachdisk holders (14) matingly engages with one of the two spindles (7, 7′)so that the disk holder (14) rotates with the respective spindles (7,7′).
 9. The apparatus according to claim 7, wherein a spacer disk (16)is located between adjacent one of the disk holders (14), and eachspacer disk (16) has a central opening (18) therein, and the centralopening (18) of the spacer disk (16) matingly engages with one of thetwo spindles (7, 7′) so that the spacer disk (16) rotates with therespective spindle (7, 7′).
 10. The apparatus according to claim 8,wherein a central opening (18) is formed in a plurality of spacer disks(16) and in the plurality of disk holders (14), the spreader brushes (8)extend from the plurality of disk holders (14) and the central openingsare formed in at least the plurality of disk holders (14) such that thebrush spreaders (8) extend therefrom at an acute angle with respect tothe rotational axis of the respective spindle (7, 7′).
 11. The apparatusaccording to claim 6, wherein a central opening (18) is formed in aplurality of spacer disks (16) and in a plurality of disk holders (14),the spreader brushes (8) extend from the plurality of disk holders (14)and the central openings are formed in at least the plurality of diskholders (14) such that the brush spreaders (8) extend therefrom at anacute angle with respect to the rotational axis of the respectivespindle (7, 7′), and the plurality of spacer disks (16) and theplurality of disk holders (14) are sandwiched between a pair ofangle-equalizing elements (15,17), and each mating surface of theplurality of spacer disks (16), the plurality of disk holders (14) andthe pair of angle-equalizing elements (15, 17) has an interlockingconnection.
 12. The apparatus according to claim 2, wherein a pluralityof spindles (7) are supported by the rotatable common rotor (9), andeach of the plurality of spindles (7) has a plurality of spacer disks(16) and a plurality of disk holders (14) with the spreader brushes (8)extend therefrom; the plurality of spacer disks (16) and the pluralityof disk holders (14) are sandwiched between a pair of angle-equalizingelements (15, 17), and a fastening element (20) is attached to a remoteend of each of the plurality of spindles (7) to retain the plurality ofspacer disks (16), the plurality of disk holders (14) and the pair ofangle-equalizing elements (15, 17).
 13. The apparatus according to claim1, wherein a plurality of spindles (7) are supported by the rotatablecommon rotor (9), and a hold down clamp (11) cooperates with eachadjacent pair of the plurality of spindles (7).
 14. The apparatusaccording to claim 13, wherein each hold down clamp (11) has roundededges.
 15. The apparatus according to claim 1, wherein the apparatus isused in combination with a drying station (12) and a conveyor (4)conveys the workpiece (2) from the apparatus to the drying station (12).16. The apparatus according to claim 1, wherein the apparatus is used incombination with a machine (5) and a conveyor (4) conveys the workpiece(2) from the machine (5) to the apparatus.
 17. The apparatus accordingto claim 1, wherein the apparatus is used in combination with a machine(5) and a drying station (12), and a conveyor (4) conveys the workpiece(2) from the machine (5) to the apparatus and then conveys the workpiece(2) from the apparatus to the drying station (12).
 18. The apparatusaccording to claim 1, wherein a plurality of spindles (7) are supportedby the rotatable common rotor (9), at least one region lying between thespindles (7) supported by the common rotor (9) has a holding-down clamp(11), the holding-down clamp (11) extends substantially parallel to thesurface (2 a) of the workpiece (2) and, on edge regions (25) of theholding-down clamp (11) facing the spindles are one of rounded andbeveled.
 19. An apparatus for one of applying and spreading a coatingonto a surface (2 a) of a workpiece (2), the apparatus comprising: fourmovable spindles and one fixed spindle (7, 7′), with each of thespindles (7, 7′) having a rotational axis arranged approximatelyparallel to the surface (2 a) of the workpiece (2) to be coated, each ofthe spindles (7, 7′) having a plurality of brush spreaders (8) supportedabout a circumference thereof, and the four movable spindles (7) beingmovable over the surface (2 a) of the workpiece (2); and the fourmovable spindles (7) are supported by a rotatable common rotor (9), thefour movable spindles and the one fixed spindle (7, 7′) each rotateabout a respective rotational axis, and the four movable spindles areguided such that the four movable spindles (7) rotate as the fourmovable spindles (7) move in a plane defined by the rotatable commonrotor (9).
 20. The apparatus according to claim 19, wherein the brushspreaders (8) are arranged around the circumference of each of thespindles (7, 7′) so as to extend at an acute angle with respect to therotational axis of the respective spindle (7, 7′), and a rotationalspeed and a rotational direction of the common rotor (9) and arotational speed and rotational direction of a driving unit (10) for theone fixed spindle (7′) are independently controllable.
 21. The apparatusaccording to claim 19, wherein the apparatus is used in combination witha machine (5) and a drying station (12), and a conveyor (4) conveys theworkpiece (2) from the machine (5) to the apparatus and then conveys theworkpiece (2) from the apparatus to the drying station (12).